Repair 7

How to Connect an A C Compound Gauge

In order to charge an air conditioning system or diagnose problems with the system, you must know how to connect and read the compound, or manifold gauges, to the vehicle. The gauges on the manifold serve two functions. They show the technician how much pressure is in the system while the AC is on, or how many inches of vacuum are in the system when discharging or evacuating. The latter is important because it is the most economical way to check for leaks in the system. The connectors on the ends of the hoses are quick-connect type connectors and the lines are color coded, making proper connection almost foolproof.

Instructions

1

Remove the cap on the high side service port, generally located in a line that runs between the compressor and the condenser, somewhere close to the condenser at the front of the vehicle. Pull back on the quick-connect ring on the red hose and push the connector onto the port. Release the ring to secure the hose to the fitting.

2

Remove the cap on the low side service port, generally located close to the firewall of the vehicle, and connect the blue hose in the same manner as the red hose.

3

Screw on the connector at the end of the yellow hose to attach it to a vacuum pump if evacuating the system after repairs or testing the system for leaks. When charging the system, screw the connector on the end of the yellow hose onto either the fitting on a 30-pound tank of refrigerant or a tapping valve if using smaller cans of refrigerant, completing the connection of the compound gauges.